New to non SAAMI Loads- 7x300Win ANY/ALL advice needed and greatly appreciated.

[Tikkad]

Hello all, I have been on this website for years now, but I mostly just dabbled. I have shot several animals at long range and steel out to a 1,000 yards- But I wouldn't say I was ever truly serious about it until now. I am diving in head first on my first true quality build. Its is a Remington 700 Action that was a 300 WM- It is now in a MPA Ultra Lite Chassis which my smith will be bedding once he blueprints and trues the action and installs the new 1:8 Twist Bartlein barrel that will be chambered in 7MM X 300 Win Mag finished at 26" plus. a lil Bastard break. He is doing some other work also like a TriggerTech trigger- But I am mostly seeking advice on anything that you wish you had known when trying to load your first non SAAMI Spec cartridge.

I have ordered some more 300 Win Mag Lapua Brass (it was good to me on my actual 300 win mag so I figure no need to change). I will be loading the 195Gr Berger Elite Hunter using Federal M215GM primers. I also plan to use VihtaVuori N565 High Energy Smokeless Rifle Powder as this is what the person building the rifle has had the best luck with on the his 7x300Win with the same barrel and chamber reamer, projectile, primer etc.

All of the brass I will be starting with for this particular rifle will be Virgin Lapua 300 WM. The thing I need the most advice on is the first re-sizing before I am ready to start load development and fire form the brass. I purchased the following die set. I also ordered a VLD Micrometer seating plug.

RED84576

REDDING 7MM/300 WINCHESTER MAG DELUXE DIE SET CUSTOM, #6

I have read that some people use the bullet seater as an itermidiatary step for sizing the neck before trying to put the virgin 300WM brass into the 7MMx300Win FL Resize die. Would you say that this is a good method and would this die set be applicable? Or would I be better off buying a second neck sizing die set up for a slightly larger bushing than the finished FL resize neck size? If that is reccomended can someone reccomend one? My set comes with a Neck sizing die, but I am actually not sure if this is a bushing style die or not as I could not find that much info on it with the Redding website being down for maintenance.

I know Redding case sizing wax is considered the gold standard by many- But my go to has been Dillon Precision DLC Case Lube for a good while now. Will this lube suffice for resizing these necks?

When I do resize this brass for the first time in the FL Die- Should I plan to set the virgin brass back 2 thousandths like I would with my fire formed brass? Or is there another finished Headspace or other measurement I should be aiming for?

I do not currently have a annealer- But I was thinking about purchasing one, and was curious to hear how big of difference any of you thought it would make on consistent neck tensions and brass life for the 7X300 Win Cartridge- Assuming it is worth it- Would it best to anneal every other reload or how often?

Any charts (trim to case length, load development) or even videos that yall know of for reloading this cartridge would be greatly appreciated.

I would also love to hear from any of you who loads this cartridge with the same N565 powder and 195GR or other weight projectiles to hear what your start/max load is? Or maybe someone who has the appropriate software could help me out?

Sorry for all of the questions- I am just really wanting to do things right on this one and am eager to learn as much as I can before I actually start. My rifle should be ready in about 3 weeks at which time I will start my load development. Also Any advise on how I can overlap load development with the fire forming of my brass would be greatly appreciated.

 

[XLR308]

Sounds like you have things pretty well figured out and if you weren't already invested so heavily in the direction you have chosen I would have recommended to just go with the 7mm PRC.
It would have saved you alot of extra steps and work primarily on the brass prep.
I would get a couple of different bushings and step down when you initially reduce the neck from 30cal to 7mm that way you won't have to worry about buckling a shoulder and damaging any of that expensive brass.
It might also be a good exercise to initially work out the process with some sacrificial brass before jumping straight into the process with your Lapua brass.
Another item to keep in mind is what your final neck thickness will be.
As in will it be a no turn neck or will the reamer dimensions be based off of the virgin brass.
Me personally I prefer using an expander mandrel and or turning arbor to set my final neck tension but I also neck turn brass even Lapua to ensure the best possible consistency even if it's just a 50% clean up.
Obviously not an absolute need as most people don't bother with that step.

 

[918v]

Why would you want to bump the shoulders back .002” on virgin brass?

 

[XLR308]

Why would you want to bump the shoulders back .002” on virgin brass?

I forgot to mention that one
When I sent my last barrel to Kelblys I dropped a note that I would only be using Lapua brass.
Not sure if it really mattered but my chamber is .0015 to .002 longer than virgin Lapua brass.
So my sized brass is pretty much the exact same dimension base to shoulder as it was new.

 

[Im2bent]

Between the 565 powder and the caliber isn't barrel life gonna be pretty short?

 

[WasNH4X]

If I were going down that road......So take the following ,with a grain of salt.
I'd want specs from reamer print in order to do some calculations ,first.
Then I'd neck size down a piece of brass ( without setting shoulder back any) and do a some measuring and compare neck O.D. and total OAL of case with print.
Some neck turning may be needed because of thickness increase during down sizing , or may not .Also necks may have to be trimmed or not.....reamer print will help to determine.
Side note: I've necked down 30-06 brass to 270 brass in one step without problems,so I don't foresee problems going from 30 to 7 mm in one step
I'd send one new brass that has been neck sized down ( neck turned and trimmed if needed per reamer print) to smith ,with the request to cut chamber to allow for .000 -.001shoulder growth when fired.
I'd also send another prepped brass with bullet seated where I plan to run it ( bearing surface of bullet out of neck/ shoulder junction ) so chamber is throated right. Considerations made for how far / close to lands bullet is intended to run.

No idea about loading data.

Now a question for O.P. : Did you ask your smith the same questions as here ?.........What he say?

Edit: spell ck

 

[WasNH4X]

Between the 565 powder and the caliber isn't barrel life gonna be pretty short?

Hey Mongo, " It's only money " who cares
Probably better barrel life than that 6.5 super duper Weatherby round .....but not by much?

 

[RegionRat]

The thing I need the most advice on is the first re-sizing before I am ready to start load development and fire form the brass.

The only example of a 7-300 WM I have worked on, did not require the steps you mentioned at all.

In fact, those types of steps like the one where you mention using the seater die for sizing down the neck, are not typical for this instance.

Since the virgin parent brass is only a little larger in the neck diameter than your goal, and you aren't really trying to change the shoulder angle or Datum Length, none of that mess applies to you.

In fact, you will only need a spread of one or two neck bushings and a Type-S die for working the neck diameter down. If you stick to one brand of brass, you may even find you always use the same bushing.

I agree with @WasNH4X. I have done wildcats where necks were moved from 30 cal down to 7mm many times. 7mm-08 was a very popular example for silhouette and hunting in the past when you had to make it from 308W.

If you start by annealing, you will get the reduction in one step and be able to go straight to final diameter. You can do this in two steps if you are shy, but I have done it in one pass many times.

The only debate, is what the reamer has for a chamber neck diameter since your brass thickness may or may not want a skim turn based on the clearance. With luck, you won't need to turn at all.

I would also love to hear from any of you who loads this cartridge with the same N565 powder and 195GR or other weight projectiles to hear what your start/max load is? Or maybe someone who has the appropriate software could help me out?

I didn't run that powder or bullet, so can't help without doing the math, and for that I would need your actual case volume and your seating depth to be able to model the recipe.

When I do resize this brass for the first time in the FL Die- Should I plan to set the virgin brass back 2 thousandths like I would with my fire formed brass? Or is there another finished Headspace or other measurement I should be aiming for?

No, on the first pass just work the neck down. If anything, you will want to run a Type-S die and bushing to get all the way down to the junction without pushing the shoulder at all.

Then, you will only test the brass fit after you establish the shoulder datum length by comparing the actual chamber to the GoGage with tape. Then only push the shoulder if your brass has a shoulder datum length that doesn't fit the chamber.

With a necked-down wildcat, a common problem can occur from a bushing not being run down the neck all the way to the junction. Leaving an over-sized radius there can cause the case to fit tight, but has nothing to do with the shoulder datum length.

Should your necked-down brass not allow the bolt to close, and after verifying that the shoulder datum isn't a cause, then you will need to inspect the neck-shoulder junction for a blend or radius problem.

This radius can sometimes cause a tight bolt closure on a necked-down design because the chamfer on Type-S bushings may not make a crisp junction. Check your bushings for a difference in the chamfers, sometimes one size is sharper than the other so flip the sharp side down.

It is best not to over-work a shoulder to cure a neck junction issue. We solve those by inverting a bushing, cutting the bushing to get a crisp junction, or by using a regular FL Neck Die to get the junction to the correct diameter.

In my opinion. it is best to have the reamer designed to create a "tight" fit to the virgin brass with these belted magnums. This shifts the headspace control from the belt to the shoulder, and that results in much smaller delta between the fire-form shots and subsequent cycles.

With the right dimensions, there is no significant difference between the first cycle and the rest such that you can hunt with the virgin brass and not feel like it doesn't perform to the same level as cycled brass.

When I sent my last barrel to Kelblys I dropped a note that I would only be using Lapua brass.
Not sure if it really mattered but my chamber is .0015 to .002 longer than virgin Lapua brass.
So my sized brass is pretty much the exact same dimension base to shoulder as it was new.

When the chamber is finished, use the Scotch-tape trick on the GoGage to establish the results. This also tells you how to expect to size the virgin brass. I recommend you don't create any extra headspace at all on the virgin cycle.

ETA: and yes, if you play in this Wildcat pool, you should be prepared to not only anneal, but to understand internal ballistics, reading pressure signs, and also how to math model for safety margin. I won't debate that our forefathers often just bagged down their rifles and pulled the trigger by a string, but we don't need to take those risks any more.

Try not to over or under think this wildcat. It is no more difficult than the 7mm-08 in terms of neck prep, but it does also bring the usual Win Mag belted brass issues.

 

[Tikkad]

Thank you all- My dies just arrived- REDDING 7MM/300 WINCHESTER MAG DELUXE DIE SET CUSTOM, #6 - It does not appear to be a bushing die so I was thinking I would try a few pieces of "sacrificial brass" through the seating die and then the Resizing die. Any big concerns before I try this? I still need to remove the factory oil from the dies and get set up so please speak now if I am setting myself up for failure.

If I were going down that road......So take the following ,with a grain of salt.
I'd want specs from reamer print in order to do some calculations ,first.
Then I'd neck size down a piece of brass ( without setting shoulder back any) and do a some measuring and compare neck O.D. and total OAL of case with print.
Some neck turning may be needed because of thickness increase during down sizing , or may not .Also necks may have to be trimmed or not.....reamer print will help to determine.
Side note: I've necked down 30-06 brass to 270 brass in one step without problems,so I don't foresee problems going from 30 to 7 mm in one step
I'd send one new brass that has been neck sized down ( neck turned and trimmed if needed per reamer print) to smith ,with the request to cut chamber to allow for .000 -.001shoulder growth when fired.
I'd also send another prepped brass with bullet seated where I plan to run it ( bearing surface of bullet out of neck/ shoulder junction ) so chamber is throated right. Considerations made for how far / close to lands bullet is intended to run.

No idea about loading data.

Now a question for O.P. : Did you ask your smith the same questions as here ?.........What he say?

Edit: spell ck

WasNH4X- He does not use Lapua brass but does use the same M215GM primer and the 195Gr Berger Elite Hunter and the same N565 powder. Please do not quote me on this as I am going to follow up with him before I make any actual loads. After he completes the build be will fire 15 rounds through it to test it with .3Gr variation on powder based off of his load development for his 7mmX300WM. if memory serves me correct then his gun likes 71.2 Grains (3,006FPS at the muzzle with the 195). Again- I will need to verify this but I can confirm it was not not over 72 Gg but it could have been closer to 70.6.

 

[WasNH4X]

Thank you all- My dies just arrived- REDDING 7MM/300 WINCHESTER MAG DELUXE DIE SET CUSTOM, #6 - It does not appear to be a bushing die so I was thinking I would try a few pieces of "sacrificial brass" through the seating die and then the Resizing die. Any big concerns before I try this? I still need to remove the factory oil from the dies and get set up so please speak now if I am setting myself up for failure.


WasNH4X- He does not use Lapua brass but does use the same M215GM primer and the 195Gr Berger Elite Hunter and the same N565 powder. Please do not quote me on this as I am going to follow up with him before I make any actual loads. After he completes the build be will fire 15 rounds through it to test it with .3Gr variation on powder based off of his load development for his 7mmX300WM. if memory serves me correct then his gun likes 71.2 Grains (3,006FPS at the muzzle with the 195). Again- I will need to verify this but I can confirm it was not not over 72 Gg but it could have been closer to 70.6.

I suggest to read /re-read ? @RegionRat post and follow his suggestions / thoughts.

I'd also suggest a talk with smith, about my thoughts about possible need to neck turn , when cross referenced with reamer print concerning possible neck thickness increase ,if any, after neck sizing down brass and measurements taken. After more thought, I doubt neck length growth will present a problem due to the already " short" neck of the 300 WM case.

What length barrel on this build?....may have been stated,but memory isn't picking up anything ATM and too lazy to re-read.

ETA: my necking down mentioned, was done with " standard " dies ,before bushing dies where a thing.

Last comment for now......this is your " cat skinning ", proceed as you wish.

 

[Tikkad]

Thanks WasNH-

I suggest to read /re-read ? @RegionRat post and follow his suggestions / thoughts.

I'd also suggest a talk with smith, about my thoughts about possible need to neck turn , when cross referenced with reamer print concerning possible neck thickness increase ,if any, after neck sizing down brass and measurements taken. After more thought, I doubt neck length growth will present a problem due to the already " short" neck of the 300 WM case.

What length barrel on this build?....may have been stated,but memory isn't picking up anything ATM and too lazy to re-read.

Thanks again WasNh4X- My barrel will be finshed at 26"+ the Brake.

 

[spife7980]

Thank you all- My dies just arrived- REDDING 7MM/300 WINCHESTER MAG DELUXE DIE SET CUSTOM, #6 - It does not appear to be a bushing die so I was thinking I would try a few pieces of "sacrificial brass" through the seating die and then the Resizing die. Any big concerns before I try this? I still need to remove the factory oil from the dies and get set up so please speak now if I am setting myself up for failure.

Run a paper towel through the dies to clean the cutting oils out. If using Dillon lube spray it in there soaking completely and then sling it out so you don’t have puddles, just a nice sheen and let it dry.
The first case lube it good, if it resists too much half way into the die take it out and relube. A couple times like that may be necessary but it should go smooth one it’s been “burnished”if you will.

 

[Tikkad]

Thanks again all, my sacraficial once fired Horandy brass was a rocky start. But then the Lapua 3x fired (True 300 win) brass that is factory annealed worked well. Now I have done a few pieces of the Lapua Virgin Brass which is factory annealed as well. I feel like it is going really well so far. I will be bringing a few pieces to my smith to get him to verify when I bring him my scope and rings when the scope gets back from Vortex (hopefully next week).